• Mysql space reduction procedure

    That ibdata1 isn't shrinking is a particularly annoying feature of MySQL. The ibdata1 file can´t actually be shrunk unless you delete all databases, remove the files and reload a dump.
    But you can configure MySQL so that each table, including its indexes, is stored as a separate file. In that way ibdata1 will not grow as large. According to Bill Karwin's comment this is enabled by default as of version 5.6 of MySQL.
    It was a while ago I did this. However, to setup your server to use separate files for each table you need to change my.cnf in order to enable this:
    As you want to reclaim the space from ibdata1 you actually have to delete the file:
    Do a mysqldump of all databases, procedures, triggers etc except the mysql and performance_schema databases
    Drop all databases except the above 2 databases
    Stop mysql
    Delete ibdata1 and ib_log files
    Start mysql
    Restore from dump
    When you start MySQL in step 5 the ibdata1 and ib_log files will be recreated.
    Now you're fit to go. When you create a new database for analysis, the tables will be located in separate ibd* files, not in ibdata1. As you usually drop the database soon after, the ibd* files will be deleted.
    You have probably seen this:
    By using the command ALTER TABLE  ENGINE=innodb or OPTIMIZE TABLE  one can extract data and index pages from ibdata1 to separate files. However, ibdata1 will not shrink unless you do the steps above.

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